Method and apparatus for distributing video packets over multiple bearers for providing unequal packet loss protection

ABSTRACT

A method and apparatus distributes video packets over multiple bearers for providing unequal packet loss protection. The method includes a packet processing function receiving a plurality of packets collectively comprising a flow of sequential data included in a sequence of media frames. For each packet, the packet processing function: applies a bearer selection process to select one of a plurality of bearers for transporting the packet over an access network, wherein each bearer has a different quality of service level which influences the probability of the transported packets being intentionally discarded by the access network, wherein the bearer selection process causes distribution of the plurality of packets across the plurality of bearers such that each bearer carries non-consecutive packets both within any given media frame and across sequential media frames and provides unequal packet loss protection for the packets in the plurality; and provides an indication of the selected bearer.

REFERENCE TO RELATED APPLICATIONS

The present application is related to the following U.S. applicationscommonly owned together with this application by Motorola, Inc.:

Ser. No. ______, filed Oct. 22, 2010, titled “Method and Apparatus forDistributing Video Packets over Multiple Bears for Providing UnequalPacket Loss Protection” by Bekiares, et al. (attorney docket no.CM13776).

TECHNICAL FIELD

The technical field relates generally to transmission of video mediaover wireless networks and more particularly to the distribution ofvideo packets over multiple bearers to provide unequal packet lossprotection for these packets while being transported over a wirelessnetwork.

BACKGROUND

Use of streaming media technology (e.g. video over Internet Protocol(IP) and voice over IP) is growing across all market segments, inclusiveof consumer, enterprise, and public safety. Today, such media iscommonly transported over wired or fixed wireless networks. However,advances in wireless broadband technology are enabling such media toalso be streamed over next generation wireless broadband networks.

Wireless networks are generally bandwidth limited with respect to thedemand for use of these networks. Contention for wireless resources,coupled with the physics of mobile wireless (e.g. signal strength,fading) typically cause great fluctuations in available bandwidthbetween any two devices communicating over the network. When bandwidthdemands of an application within a source device exceed instantaneousbandwidth available on the network, packet loss occurs.

This is an important consideration, as the packet loss pattern inflictedon streaming media, such as audio and video, has ramifications on thequality of the media when it is reproduced at a destination device.Notably, some amount of random-like packet loss within a media stream isanticipated, and can be effectively concealed by an error resilientdecoder. Overloaded best effort transmission queues, however, typicallydo not inflict random-like packet loss upon a media stream, but ratherindiscriminately drop or delay long chains of consecutive packets.Consecutive packet loss, as opposed to random-like packet loss, willcause significantly degrading artifacts in the decoded media quality.

As noted above, some amount of packet loss is unavoidable due to theconstrained nature of wireless networks. Furthermore, uncontrolledpacket loss can lead to significantly degraded media quality.

Thus, there exists a need for a mechanism to control which video packetsare discarded by a wireless network, thereby, providing unequal packetloss protection in such a way as to optimize decoded media quality.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, which together with the detailed description below areincorporated in and form part of the specification and serve to furtherillustrate various embodiments of concepts that include the claimedinvention, and to explain various principles and advantages of thoseembodiments.

FIG. 1 is a diagram of a communication system that implementsdistribution of video packets over multiple bearers for providingunequal packet loss protection in accordance with some embodiments.

FIG. 2 is a flow diagram illustrating a method for distributing videopackets over multiple bearers for providing unequal packet lossprotection in accordance with some embodiments.

FIG. 3 is a flow diagram illustrating a method for bearer selection inaccordance with some embodiments.

FIG. 4 illustrates the bearer selection method of FIG. 3, as applied tovideo frames.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to helpimprove understanding of various embodiments. In addition, thedescription and drawings do not necessarily require the orderillustrated. It will be further appreciated that certain actions and/orsteps may be described or depicted in a particular order of occurrencewhile those skilled in the art will understand that such specificitywith respect to sequence is not actually required. Apparatus and methodcomponents have been represented where appropriate by conventionalsymbols in the drawings, showing only those specific details that arepertinent to understanding the various embodiments so as not to obscurethe disclosure with details that will be readily apparent to those ofordinary skill in the art having the benefit of the description herein.Thus, it will be appreciated that for simplicity and clarity ofillustration, common and well-understood elements that are useful ornecessary in a commercially feasible embodiment may not be depicted inorder to facilitate a less obstructed view of these various embodiments.

DETAILED DESCRIPTION

Generally speaking, pursuant to the various embodiments, a method andapparatus distributes video packets over multiple bearers for providingunequal packet loss protection. The method includes a packet processingfunction receiving a plurality of packets collectively comprising a flowof sequential data included in a sequence of media frames. For eachpacket, the packet processing function: applies a bearer selectionprocess to select one of a plurality of bearers for transporting thepacket over an access network, wherein each bearer has a differentquality of service level which influences the probability of thetransported packets being intentionally discarded by the access network,wherein the bearer selection process causes a distribution of theplurality of packets across the plurality of bearers such that eachbearer carries non-consecutive packets both within any given media frameand across sequential media frames and provides unequal packet lossprotection for the packets in the plurality; and provides, to an accessnetwork entity, an indication of the selected bearer.

The disclosed teachings cause a random-like dropping of media packets bya network during times of network bandwidth constraint, resulting in anoverall better quality of media at a receiving function than when thenetwork indiscriminately drops consecutive packets Those skilled in theart will realize that the above recognized advantages and otheradvantages described herein are merely illustrative and are not meant tobe a complete rendering of all of the advantages of the variousembodiments.

Referring now to the drawings, and in particular FIG. 1, a communicationsystem that implements distribution of video packets over multiplebearers for providing unequal packet loss protection in accordance withsome embodiments is shown and indicated generally at 100. In general,the system 100 includes a media sourcing function 102 having anapplication (not shown) that provides a sequence of media frames witheach frame having one or more packets that are received into a packetprocessing function 110 that applies a bearer selection process orfunction in accordance with the present teachings in order to distributethe packets over multiple bearers (e.g., 112, 114) having unequalpriority, for transport over one or more access networks 116 to a mediareceiving function 120.

The media sourcing function 102 may be included, for example, as anelement of the infrastructure of a consumer, enterprise, or publicsafety network or as an element of a User Equipment (UE) device andincludes one or more of: an application (e.g., Push-to-Video), storedmedia files or a media encoding function, etc.

In this illustrative implementation, the media sequence comprises asuccession of multiple media frames. For example, FIG. 1 shows the mediasourcing function 102 sourcing video frames F0 (104), F1 (106), and F2(108), in a sequence over time (however, the present teachings areequally applicable to a media sequence comprising one or more audioframes sourced in a sequence). For efficient transport, each media frameis further divided into smaller blocks of data termed herein, ingeneral, as “packets” (but also referred to in the art as datagrams, andthe like, depending on the particular protocols used).

It follows then that video frames, for example, are typically split intomultiple packets, with each packet containing a portion of the spatialdata for the video frame. That spatial data is typically organized in alinear raster-scan fashion (i.e. top-to-bottom, left-to-right), as canbe seen by packets P0 through P8, contained within frames F0, F1, and F2of FIG. 1. As such, the data contained in neighboring video packets istypically collocated in a spatial and temporal fashion in thecorresponding video frames. Notably, the amount of spatial data encodedinto each packet is also typically fixed and constant across packets.Thus, the spatial area described by packet P1 is the same spatial areasubsequently described by Packets P4 and P7.

Moreover, the media sourcing function 102 uses various protocols such asInternet Protocol (e.g., IP v 4 or IP v 6, described in InternetEngineering Task Force (IETF) Requests for Comments (RFC) 791 and 2460,respectively), User Datagram Protocol (UDP) (e.g., as described in IETFRFC 768), Real-Time Protocol (RTP) (e.g., as described in IETF RFC 3550)to format the frames and packets in such a way as to enable routing ofthe packets to the intended destination and to enable reassembly anddecoding of the frames at the destination device.

The packet processing function 110 is a logical entity that receives themedia packets and applies a bearer selection process or algorithm (forexample, as part of a method as described below by reference to FIG. 2and FIG. 3) to determine the bearer on which to send each packet. Inaccordance with the teachings herein, the bearer selection processcauses a distribution of the plurality of packets across the pluralityof bearers such that each bearer carries non-consecutive packets bothwithin any given media frame and across sequential media frames. As theterm is used herein, “consecutive” packets are packets which areconsecutive within a given media frame or, in the case of video media,encode the same spatial area across consecutive media frames. By way ofexample, referring to FIG. 4, PACKET 0 and PACKET 1 of FRAME 0 areconsecutive, as are PACKET 0 of FRAME 0 and PACKET 4 of FRAME 1.Conversely, PACKET 0 and PACKET 2 of FRAME 0 are non-consecutive, as arePACKET 3 of FRAME 0 and PACKET 4 of FRAME 1, as are PACKET 0 of FRAME 0and PACKET 8 of FRAME 2. Returning to FIG. 1, the packet processingfunction 110 may reside on any number of devices within network 100,separately or distributed over multiple devices.

In one network configuration, the media sourcing function 102 isconnected to the infrastructure of the access network. On the downlinkfrom the media sourcing function 102 to the media receiving function 120(as illustrated in FIG. 1), the packet processing function 110 could beincluded in the media sourcing function 102, within an access network116 entity (i.e., an entity included in one of the access networks 116,such as within a Policy and Charging Rules Function (PCRF) within a LongTerm Evolution (LTE) network), as a stand alone device (as illustrated)or be distributed across multiple of such devices. In another networkconfiguration, the media sourcing function 102 is connected to thewireless interface of the access. On the uplink from the media sourcingfunction 102 to the media receiving function 120, the packet processingfunction could similarly be implemented in the media sourcing function102 or as a stand alone device or be distributed across multiple of suchdevices.

Access networks 116 comprise infrastructure devices used for managingthe allocation and maintenance of bearer resources for the transport ofmedia traffic such as video and audio packets. Access networks 116 caninclude one or more access networks in any combination that provide thecommunication resources over which the media is transported. Examples ofsuch access networks include, but are not limited to, one or more 3^(rd)Generation Partnership Project (3GPP) networks such as LTE, one or moreRadio Access Networks (RANs) (e.g., an E-UTRAN (Evolved UMTS TerrestrialRadio Access Network), any 2G RAN, such as, Global System for MobileCommunication (GSM), any 3G RAN, such as CDMA EVDO, or any 4G RAN, suchas WiMAX), or one or more Wireless LAN (WLANs), such as 802.11, or anyother suitable wireless or wired access network with provisions forassociating a quality of service with a bearer for transporting mediatraffic.

Within broadband networks, such as LTE, one or more bearers (e.g., 112,114) may be allocated for transporting of the packets over the network.As the term is used herein, a “bearer” is a virtual concept thatrepresents an allocation of physical resources over the access networksfor transporting identified media traffic (also referred to in LTE asService Data Flows (SDFs)), such as the video packets, and is associatedwith a quality of service (QoS) level (also, interchangeably, referredto herein as a priority level), which influences the probability of thetransported packets being dropped.

In LTE, for example, a bearer can be a dedicated bearer or a defaultbearer. A default bearer is defined as a non-GBR (guaranteed bit rate)bearer that provides for “best effort” SDF transmission and is allocatedto a UE for the duration of its attachment to the LTE network and neednot be explicitly requested. A dedicated bearer is defined as anyadditional bearer that is established for the same UE and isspecifically requested by (or on behalf of) a UE and can be eithernon-GBR or GBR, having a certain allocated or associated QoS or prioritylevel as quantified by one or more QoS attributes, characteristics orparameters such as packet delay, packet loss rate, guaranteed or minimumbit rate, pre-emption capability, etc. Moreover, in LTE, QoS or prioritylevel is specified in terms of such parameters as Allocation andRetention Priority (ARP), QoS Class Identifier (QCI), Maximum Bit Rate(MBR), Guaranteed Bit Rate (GBR), etc, which influences the probabilityof the transported packets being dropped, as follows.

For example, where an application wants to provide unequal or differentlevels of packet loss protection to certain packets when said packetsare transported over the access networks 116, the application requestsand is granted or allocated bearers having different priority (meaningquality of service) levels, e.g., bearers 112 and 114, respectively,having priority level X (which has the lower priority of the twobearers) and X+1, wherein X is the overall priority of the media flowwith respect to other prioritized traffic. In theory, the applicationcould request and reserve any number, N, of bearers, as allowed by thecontrolling protocol. In such a case, the N allocated bearers would havepriority X+Y(N), where X is still the overall priority of the media flowwith respect to other prioritized traffic, and where Y(N) (and theassociated priority level of the bearer) is monotonically decreasingfrom [N−1] to 0, with X being the lowest priority level.

Accordingly, when the network is experiencing congestion 118, thenetwork intentionally selects packets to drop based on the prioritylevel assigned to the bearer over which the packets are transported.Thus, the higher the priority level of the bearer, the lower theprobability of the network dropping or discarding packets beingtransported on the associated bearer, as compared to packets beingtransported on bearers having a lower priority level. Stated anotherway, the network will intentionally discard packets transported overbearers with lower priority levels before discarding packets beingtransported on bearers having higher priority levels, thereby, providingthe unequal packet loss protection for the packets. This can be done ona packet by packet basis or the network may rescind a bearer altogether,such that the bearer is no longer available for transporting packets.

As mentioned above, priority level can be set by setting certain QoSparameters alone or in combination. For example, the unequal prioritylevel of bearers 112, 114 could be enabled by assigning the bearersdifferent ARP values, which influences the probability of the bearerbeing rescinded or pre-empted by the establishment of another bearer fortraffic having a higher priority. The unequal priority level can also beenabled by assigning the bearers different QCI values, which controlcharacteristics like packet delay, packet error loss rate, guaranteed orminimum bit rate, which in turn influence the probability of thetransported packets being dropped. Also, the unequal priority levelcould be set by some combination of QCI value and ARP value. The exactmeans by which priority of a bearer, or the probability of the packetstransported over said bearer being dropped, is expressed is dependentupon what quality of service parameters are supported by the network. Bydirecting specific traffic to specific bearers, an application orintermediary function can control specifically which packets will bedropped when the network is no longer able to sustain a given bit rate.

The media receiving function 120 is a logical entity which receivesmedia from the media sourcing function 102 by way of the access network116. It may be included in any number of infrastructure and UE elements,the latter of which are also referred to in the art as subscribers orsubscriber units, communication devices, access devices, accessterminals, mobile stations, mobile subscriber units, mobile devices,user devices, and the like, and can be any type of communication devicesuch as radios, mobile phones, mobile data terminals, Personal DigitalAssistants (PDAs), laptops, two-way radios, cell phones, and any otherdevice capable of operating in a wired or wireless environment and thatcan be used by public users (such as commercial users) or private users(such as public safety users).

In general, the media sourcing function 102 (and its associatedapplications), packet processing function 110, access network 116entities, and the media receiving function 120 (and its associatedapplications) are each implemented using (although not shown) a memory,one or more network interfaces, and a processing device that areoperatively coupled, and which when programmed form the means for thesesystem elements to implement their desired functionality, for example asillustrated by reference to the methods shown in FIG. 2 and FIG. 3. Thenetwork interfaces are used for passing signaling, (e.g., messages,packets, datagrams, frames, superframes, and the like) between theelements of the system 100. The implementation of the network interfacein any particular element depends on the particular type of network,i.e., wired and/or wireless, to which the element is connected.

Where the network supports wireless communications, the interfacescomprise elements including processing, modulating, and transceiverelements that are operable in accordance with any one or more standardor proprietary wireless interfaces, such as EVDO, WCDMA, LTE, WiMax,WiFi, and the like, wherein some of the functionality of the processing,modulating, and transceiver elements may be performed by means of theprocessing device through programmed logic such as software applicationsor firmware stored on the memory device of the system element or throughhardware.

The processing device utilized by these elements may be programmed withsoftware or firmware logic or code for performing functionalitydescribed by reference to FIG. 2 and FIG. 3; and/or the processingdevice may be implemented in hardware, for example, as a state machineor ASIC (application specific integrated circuit). The memoryimplemented by these system elements can include short-term and/orlong-term storage of various information needed for the functioning ofthe respective elements. The memory may further store software orfirmware for programming the processing device with the logic or codeneeded to perform its functionality.

Turning now to FIG. 2, a flow diagram illustrating a method fordistributing video packets over multiple bearers for providing unequalpacket loss protection is shown and generally indicated at 200. Method200 is performed in the packet processing function 110, and will bedescribed in conjunction with the elements and packets shown in FIG. 1.Accordingly, at 202, the packet processing function 110 receives aplurality of packets from the media sourcing function 102, whichcollectively include a flow of sequential data included in a sequence ofmedia frames. For instance, the packet processing function 110 receivesa media stream from the media sourcing function 102, which comprisesvideo frames F1 (having packets P0, P1, and P2), F2 (having packet P3,P4, and P5) and F3 (having packets P6, P7, and P8).

In one illustrative implementation, the media sourcing functionimplements Internet Protocol and RTP to format and send the videopackets. Accordingly, an IP header is added to each packet to facilitaterouting in the network. Included in the IP header is information such asbut is not limited to, information identifying a source IP address orIPv6 network prefix for the sending application, a destination IPaddress or IPv6 network prefix for the receiving application, a sourceport number, a destination port number, and a protocol ID of theprotocol above IP (collectively referred to in the art as the “IP 5tuple” since there are five parameters).

Moreover, a RTP header is added to each packet. Included in the RTPheader is information such as, but not limited to, a timestamp value,indicating the relationship between packets and media frames and asequence number value, indicating the relative ordering of packets inthe media stream. To determine the corresponding frame and informationabout the frame, the packet processing function 110, for instance, candetermine from the timestamp value in the RTP header the numbered frameto which the packet belongs and the relative location of that frame inthe media sequence.

Returning again to method 200, for each packet in the media stream, thepacket processing function 110 applies (204) a bearer selection processto select one of a plurality of bearers for transporting the packet overan access network, wherein each bearer has a different quality ofservice level which influences the probability of the transportedpackets being intentionally discarded by the access network, wherein thebearer selection process causes a distribution of the plurality ofpackets across the plurality of bearers such that each bearer carriesnon-consecutive packets both within any given media frame and acrosssequential media frames, in accordance with various embodiments of theteachings herein. It should be noted that, in the present embodiment, itis immaterial which set of non-consecutive packets are assigned to agiven bearer. The present teachings are designed to prevent consecutivepacket loss, both within any given media frame and across sequentialmedia frames, but not to identify certain media packets as being more orless significant to the quality of the media decoding.

One simple bearer selection methodology, when two bearers are allocated,comprises selecting a different one of the two bearers for every otherpacket processed. This methodology works well for audio packets, whereinthere is one packet per audio frame, and for the packet sequence shownin packets 104, 106, and 108 of FIG. 1, wherein there are an odd numberof packets (in this case three) comprising every video frame. In thisexample, packet loss will be intentionally well distributed across theframes, rather than being consecutive across some or all of the packetscomprising frames 104, 106, and 108. Notably, lost spatial dataoccupying a specific region of a given video frame (e.g. packets P1 andP7) are bounded in time with received data for that same spatial region(e.g. Packets P4 and a packet in the same spatial area from the nextframe in the sequence (not shown)). This will minimize additive errorsand limit error propagation in this spatial region of the frame.Furthermore, by preventing consecutive packet loss within a frame, arobust decoder is able to further interpolate lost data (e.g. Packet P1)from neighboring received data for the same frame (e.g. Packets P0 andP2).

However, this simple algorithm does not always work and other algorithmsare needed, for example, to process packets from media frames. In oneillustrative bearer selection process, the packet processing function110 selects a high priority level bearer for a first set ofnon-consecutive media packets and a low priority bearer level for asecond set of non-consecutive media packets. Thus, packets present inthe first set of non-consecutive media packets have the least relativeprobability of being dropped by the network when network bandwidth isconstrained, while packets in the second set of non-consecutive mediapackets have the most relative probability of being dropped by thenetwork when network bandwidth is constrained. Thus, when the network isbandwidth constrained, the media receiving devices will receive only thefirst set of non-consecutive packets, closely approximating randompacket loss conditions under which error concealment algorithms performoptimally, and thus resulting in an overall better quality of media at areceiving function than when the network indiscriminately dropsconsecutive packets.

For instance, FIG. 3 illustrates a more particular example of a bearerselection process 300 performed by the packet processing function 110,in accordance with the present teachings. Method 300 includes:identifying (302) the sequence number and the timestamp value;determining (304), using the timestamp value, whether the packet hasdata from an even or odd numbered media frame; determining (306), usingthe sequence number, whether the packet is an even or odd numberedpacket within the media frame; for the even-numbered frames, selecting(308) the first bearer for the even numbered packets, and selecting thesecond bearer for the odd-numbered packets; for the odd-numbered frames,selecting (310) the first bearer for the odd-numbered packets, andselecting the second bearer for the even-numbered packets.

Another illustrative algorithm for bearer selection is as follows:

1. For a new media flow:

-   -   a. If required to enable prioritized packet handling in the        underlying network which provides connectivity to the intended        recipient, establish/reserve two bearers in the underlying        network, one with priority X+Y, and one with priority X, where X        is the overall priority of the media flow with respect to other        prioritized traffic, and Y>=1.

2. Identify which packets of a given media flow comprise a given mediaframe (e.g. by examining the timestamp value).

3. Identify sequence numbers of packets within the given media flow.

4. For even-numbered media frames (as determined by the timestampvalue),

-   -   a. associate even-numbered packets (as determined by the        sequence number value) of the even-numbered media frame with a        first set of non-consecutive packets.    -   b. associate odd-numbered packets of the even-numbered media        with a second set of non-consecutive packets.

5. For odd-numbered media frames,

-   -   a. associate odd-numbered packets of the odd-numbered media        frame with a first set of non-consecutive packets.    -   b. associate even-numbered packets of the odd-numbered media        frame with a second set of non-consecutive packets.

6. Direct packets to network bearers (as determined by non-consecutiveset association)

-   -   a. Direct packets associated with a first set of non-consecutive        packets to the bearer with priority X+Y, where X is the overall        priority of the media flow with respect to other prioritized        traffic, and Y>=1.    -   b. Direct packets associated with a second set of        non-consecutive packets to the bearer with priority X, where X        is the overall priority of the media flow with respect to other        prioritized traffic.        Employing this algorithm produces an illustrative assignment 400        of packets within media frames 402, 404, and 406 shown in        FIG. 4. Notably, the specific algorithm iterated above is        applicable for both audio and video streaming media, regardless        of the number of packets comprising a media frame.

Looking back at the media stream transmitted by the media sourcingfunction 102, two bearers 112 and 114 were established for this mediastream. Accordingly, bearer 114 (with the higher priority) is selectedto transport packets from the first set of non-consecutive packets,wherein illustratively shown are packets P0 from frame F0 (104), P2 fromframe F0, and P4 from frame F1 (106) are shown being transported usingbearer 114. Moreover, bearer 112 (with the lower priority) is selectedto transport packets from the second set of non-consecutive packets,wherein illustratively shown are packets P1 from frame F0 (104), P3 fromframe F1 (106), and P5 from frame F1 are shown being transported usingbearer 112. It should be noted that the above algorithm, which dividesconsecutive media packets equally across two available bearers, ismerely illustrative, and instead could be embodied in such a way as todivide the packets across more than two bearers so long as the algorithmensures that consecutive media packets are always placed onto bearerswith differing levels of priority.

To facilitate the packets being transported over the correct bearer, thepacket processing function 110 provides (206) to an access networkentity an indication of the selected bearer for each packet. This can bedone in a number of ways. For example, in one illustrativeimplementation, the packet processing function 110 places some type ofvalue or bits into one or more of the headers on the packet for thenetwork entity to use in identifying the appropriate bearer. Forexample, the value is inserted into a Type of Service field of an IPversion 4 header (e.g., a TOS value) or in a Flow Identifier field of anIP version 6 header, which allows a Packet Data Gateway in a LTE networkto match the packet, via the inserted value, to a Service Data FlowTemplate or Traffic Flow Template (TFT) (corresponding to the selectedbearer), which corresponds to the same value.

As stated earlier, various QoS parameters can be used to set the unequalor different priority levels for the allocated bearers. For instance, ina LTE environment, the same “latency” may be imposed on all allocatedbearers to ensure that packets arrive on-time, and roughly in order.Moreover, not all bearer reservations need to be associated with aGuaranteed Bit Rate. One bearer may be GBR, while the other may beNon-GBR with a low-latency requirement. In addition, each bearer can becharacterized by a different QCI value for providing the differentpriority levels.

Also, each bearer can be characterized by a different ARP value forproviding the different priority levels. In a further implementationscenario, a highest priority bearer in the plurality of bearers is notpreemptable (e.g., bearer 114), and at least one of the other lowerpriority bearers (e.g., bearer 112) is preemptable, based on the settingof the ARP values. This can be done by setting for the first (highestpriority) bearer the “not pre-emptable” flag (to ensure that it remainsreserved if possible), along with the “can pre-empt” flag (indicating itshould preempt existence of other pre-emptable bearers, such assecondary, tertiary, and lower priority bearers of other streams). Othersecondary, tertiary, and lower priority bearers have the “ispre-emptable” flag set (indicating that the first bearers of otherstreams may preempt this bearer if necessary).

Thus, when the network is forced to ultimately rescind a bearerreservation such as from congestion 118 in the network, it will dropbearer 112 (and its associated packets) and then bearer 114. Whentransporting video, it is generally better to altogether drop trafficintended for the rescinded bearer, rather than allowing it to flow ontothe default bearer. This may be advantageous, as the best effortstreaming media data will likely arrive too late for the media decodingprocess, needlessly consuming bandwidth which would be better occupiedby other, non-time-sensitive, best effort applications.

As shown in FIG. 1, when the network 116 selects bearer 112 to rescind,the packets (e.g., P1, P3, P5) being transported using that bearer arediscarded or dropped. However, the media receiving function 120continues to receive the packets (e.g., P0, P2, P4) transported usingbearer 114. According, using the disclosed teachings, packet loss iswell distributed over the frames which has a less detrimental effect ondecoded spatial quality than packets dropped in a sequential fashion.

In the foregoing specification, specific embodiments have beendescribed. However, one of ordinary skill in the art appreciates thatvarious modifications and changes can be made without departing from thescope of the invention as set forth in the claims below. Accordingly,the specification and figures are to be regarded in an illustrativerather than a restrictive sense, and all such modifications are intendedto be included within the scope of present teachings. For example, themethod steps described herein and illustrated within the drawings do notnecessarily require the order shown unless explicated stated herein. Assuch, the steps described may be taken out of sequence and come stepsmay be performed simultaneously and still fall within the scope of theteachings and the claims herein. In addition, benefits, advantages,solutions to problems, and any element(s) that may cause any benefit,advantage, or solution to occur or become more pronounced are not to beconstrued as a critical, required, or essential features or elements ofany or all the claims. The invention is defined solely by the appendedclaims including any amendments made during the pendency of thisapplication and all equivalents of those claims as issued.

Moreover in this document, relational terms such as first and second,top and bottom, and the like may be used solely to distinguish oneentity or action from another entity or action without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions. The terms “comprises,” “comprising,” “has”,“having,” “includes”, “including,” “contains”, “containing” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises, has,includes, contains a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. An element proceeded by“comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . .a” does not, without more constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises, has, includes, contains the element. The terms“a” and “an” are defined as one or more unless explicitly statedotherwise herein. The terms “substantially”, “essentially”,“approximately”, “about” or any other version thereof, are defined asbeing close to as understood by one of ordinary skill in the art, and inone non-limiting embodiment the term is defined to be within 10%, inanother embodiment within 5%, in another embodiment within 1% and inanother embodiment within 0.5%. The term “coupled” as used herein isdefined as connected, although not necessarily directly and notnecessarily mechanically. A device or structure that is “configured” ina certain way is configured in at least that way, but may also beconfigured in ways that are not listed.

It will be appreciated that some embodiments may be comprised of one ormore generic or specialized processors (or “processing devices”) such asmicroprocessors, digital signal processors, customized processors andfield programmable gate arrays (FPGAs) and unique stored programinstructions (including both software and firmware) that control the oneor more processors to implement, in conjunction with certainnon-processor circuits, some, most, or all of the functions of themethod and apparatus for distribution of video packets over multiplebearers to provide unequal packet loss protection for these packetswhile being transported over a wireless network described herein. Thenon-processor circuits may include, but are not limited to, a radioreceiver, a radio transmitter, signal drivers, clock circuits, powersource circuits, and user input devices. As such, these functions may beinterpreted as steps of a method to perform the distribution of videopackets over multiple bearers to provide unequal packet loss protectionfor these packets while being transported over a wireless networkdescribed herein. Alternatively, some or all functions could beimplemented by a state machine that has no stored program instructions,or in one or more application specific integrated circuits (ASICs), inwhich each function or some combinations of certain of the functions areimplemented as custom logic. Of course, a combination of the twoapproaches could be used. Both the state machine and ASIC are consideredherein as a “processing device” for purposes of the foregoing discussionand claim language.

Moreover, an embodiment can be implemented as a computer-readablestorage element or medium having computer readable code stored thereonfor programming a computer (e.g., comprising a processing device) toperform a method as described and claimed herein. Examples of suchcomputer-readable storage elements include, but are not limited to, ahard disk, a CD-ROM, an optical storage device, a magnetic storagedevice, a ROM (Read Only Memory), a PROM (Programmable Read OnlyMemory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM(Electrically Erasable Programmable Read Only Memory) and a Flashmemory. Further, it is expected that one of ordinary skill,notwithstanding possibly significant effort and many design choicesmotivated by, for example, available time, current technology, andeconomic considerations, when guided by the concepts and principlesdisclosed herein will be readily capable of generating such softwareinstructions and programs and ICs with minimal experimentation.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

1. A method for providing unequal packet loss protection in a network,the method comprising: a packet processing function performing:receiving a plurality of packets collectively comprising a flow ofsequential data included in a sequence of media frames; for each packetin the plurality, applying a bearer selection process to select one of aplurality of bearers for transporting the packet over an access network,wherein each bearer has a different quality of service level whichinfluences the probability of the transported packets beingintentionally discarded by the access network, wherein the bearerselection process causes a distribution of the plurality of packetsacross the plurality of bearers such that each bearer carriesnon-consecutive packets both within any given media frame and acrosssequential media frames and provides unequal packet loss protection forthe packets in the plurality; and providing, to an access networkentity, an indication of the selected bearer.
 2. The method of claim 1,wherein each packet includes a timestamp value and a sequence number,wherein the plurality of bearers comprises a first bearer having a firstquality of service level and a second bearer having a second quality ofservice level, and applying the bearer selection process comprises: foreach packet in the plurality, identifying the sequence number and thetimestamp value; determining, using the timestamp value, whether thepacket has data from an even or odd numbered media frame; determining,using the sequence number, whether the packet is an even or odd numberedpacket within the media frame; for the even-numbered frames, selectingthe first bearer for the even numbered packets, and selecting the secondbearer for the odd-numbered packets; for the odd-numbered frames,selecting the first bearer for the odd-numbered packets, and selectingthe second bearer for the even-numbered packets.
 3. The method of claim2, wherein the data comprises video data.
 4. The method of claim 2,wherein each packet comprise a Real Time Protocol header that includesthe timestamp value and the sequence number.
 5. The method of claim 1,wherein providing the indication of the selected bearer comprisesinserting a value within the packet, wherein the value is used by theaccess network entity to transport the packet using the selected bearer.6. The method of claim 5, wherein the packet includes an InternetProtocol header, and the value is inserted into a Type of Service fieldof the Internet Protocol header.
 7. The method of claim 5, wherein thepacket includes an Internet Protocol header, and the value is insertedinto a Flow Identifier field of the Internet Protocol header.
 8. Themethod of claim 1, wherein each bearer in the plurality is characterizedby a different Allocation and Retention Priority (ARP) value forproviding the different quality of service levels.
 9. The method ofclaim 8, wherein a highest quality of service bearer in the plurality ofbearers is not preemptable, and at least one of the other lower qualityof service bearers is preemptable.
 10. The method of claim 1, whereineach bearer in the plurality is characterized by a different QoS ClassIdentifier (QCI) value for providing the different quality of servicelevels.
 11. The method of claim 1, wherein the plurality of bearerscomprises two bearers, and wherein applying the bearer selection processcomprises selecting a different one of the two bearers for every otherpacket processed.
 12. The method of claim 11, wherein the data compriseaudio data.
 13. A packet processing function for distributing videopackets over multiple bearers for providing unequal packet lossprotection, the packet processing function comprising: an interface thatreceives a plurality of packets collectively comprising a flow ofsequential data included in a sequence of media frames; and a processingdevice that: for each packet in the plurality, applies a bearerselection process to select one of a plurality of bearers fortransporting the packet over an access network, wherein each bearer hasa different quality of service level which influences the probability ofthe transported packets being intentionally discarded by the accessnetwork, wherein the bearer selection process causes a distribution ofthe plurality of packets across the plurality of bearers such that eachbearer carries non-consecutive packets both within any given media frameand across sequential media frames and provides unequal packet lossprotection for the packets in the plurality; and provides, to an accessnetwork entity, an indication of the selected bearer.
 14. The packetprocessing function of claim 13, where the packet processing functionresides in a User Equipment (UE) device.
 15. The packet processingfunction of claim 13, where the packet processing function resides in aninfrastructure device.
 16. A computer-readable storage element havingcomputer readable code stored thereon for programming a computer toperform a method for distributing video packets over multiple bearersfor providing unequal packet loss protection, the method comprising:receiving a plurality of packets collectively comprising a flow ofsequential data included in a sequence of media frames; for each packetin the plurality, applying a bearer selection process to select one of aplurality of bearers for transporting the packet over an access network,wherein each bearer has a different quality of service level whichinfluences the probability of the transported packets beingintentionally discarded by the access network, wherein the bearerselection process causes a distribution of the plurality of packetsacross the plurality of bearers such that each bearer carriesnon-consecutive packets both within any given media frame and acrosssequential media frames and provides unequal packet loss protection forthe packets in the plurality; and providing, to an access networkentity, an indication of the selected bearer.